Andreaea alpestris (Thed.) Schimp. in B.S.G., Bryol. Eur. 6: 146. 1855. A. petrophila Ehrh. var. alpestris Thed., Bot. Not. 5: 79. 1849. A. rupestris Hedw. var. alpestris (Thed.) Sharp in Grout, Moss Fl. N. Amer. 1: 2. 1936. Type. Sweden, Thedenius.
Plants small, 1–2 cm high. Leaves without a whitish bloom, imbricate-appressed, lanceolate, concave, weakly cucullate above, somewhat constricted above the base, weakly panduriform, 0.5–1.0 mm long, apices straight, obtuse; margins erect somewhat incurved above; lamina unistratose or bistratose in streaks; ecostate; upper leaf cells irregularly short rectangular to quadrate or oval, 7–10 µm ×5 µm, firm-walled to incrassate, not pitted; lower leaf cells 12–30 µm × 7 µm, yellowish, long-rectangular, incrassate, pitted and sinuous; cells smooth or with low, weak dorsal papillae. Perichaetial leaves differentiated, sheathing, convolute. Sporophytes as in the genus. Spores not seen.